In order to write data to media, a write head is typically used. Such a write head is generally part of a merged head that includes a head for writing and a head for reading data from the media. FIGS. 1A and 1B depict side and perspective views, respectively, of a portion of a conventional insulation-defined zero-throat (IDZT) write head 10. The conventional IDZT head 10 includes a conventional first pole (P1) 12 and a conventional second pole (P2) 20 that are separated at the front, near the air bearing surface, by a conventional gap 18. Also shown is the hardbake layer 22 that is typically photoresist that is used to insulate the coils (not shown) of the conventional IDZT head 10. The conventional P1 12 includes a conventional pedestal 14 that has a conventional notch 16. The conventional notch 16 is typically formed by milling a portion of the pedestal 14. In forming the notch 16 using a conventional process, the hardbake 22 is used as a mask to shadow a portion of the conventional P1 12 from the ion mill. Thus, as can be seen in FIG. 1A, the hardbake layer 22 is relatively close to the front of the conventional IDZT head 10. The hardbake layer 22 thus overlaps a portion of the conventional pedestal 14. Because of the process used in its formation, the front 15 of the conventional notch 16 is thinner than the back 17 of the conventional notch 16.
Although the conventional IDZT head 10 functions, one of ordinary skill in the art will readily recognize that the writeability of the conventional IDZT head 10 can be improved. Furthermore, the track width, which is defined using the conventional notch 16 may be difficult to control.
FIGS. 2A and 2B depict side and perspective views, respectively, of a more recently developed pedestal-defined zero throat (PDZT) head 50. The more recently developed PDZT head 50 includes a conventional first pole (P1) 52 having a conventional pedestal 54, a conventional second pole (P2) 60 and a conventional gap 58 separating the conventional P1 52 from the conventional P2 60. The more recently developed PDZT head 50 also includes a hardbake layer 62 used to insulate coils (not shown). As can be seen in comparing FIG. 2A to FIG. 1A, the conventional hardbake layer 62 has been moved farther from the front of the more recently developed PDZT head 50. As a result, there is no overlap between the pedestal 54 and the hardbake layer 62.
The conventional pedestal 54 also includes a conventional notch 56 The conventional notch 56 is formed by using the conventional P2 60 as a mask to shadow the pedestal 54 during the milling process which forms the notch 56. Because the P2 60 is used as a mask, the ability of the more recently developed PDZT head 50 to write to a media is improved over that of the conventional PDZT head 10 depicted in FIGS. 1A and 1B. Referring back to FIGS. 2A and 2B, the process used for forming the notch 56 can also allow for greater control of the size of the notch 56 and, therefore, the track width.
Although the more recently developed PDZT head 50 functions, one of ordinary skill in the art will readily recognize that the more recently developed PDZT head 50 may inadvertently erase tracks adjacent to the track currently being written. FIGS. 3A and 3B depict portions of the more recently developed PDZT head 50 along with the magnetic field generated during use of the more recently developed PDZT head 50. As can be seen in FIGS. 3A and 3B, the magnetic flux generated between P1 52 and P2 60 includes gap flux in the gap 58 between the notch 56 and the P2 60 as well as a fringe flux at the edges of the pedestal 54 and the P2 60. This fringe flux includes flux at the back 57 of the notch 56, as shown in FIG. 3B. The combination of the fringe flux and the gap flux increase the magnetization of the pedestal 54 near the notch 56. In particular, the bottom of the notch 56 may become saturated. This can generate a longitudinal field (perpendicular to the plane of the page in FIG. 3B) at the front of the notch 56. This longitudinal field can inadvertently erase adjacent tracks.
Accordingly, what is needed is a system and method for reducing the tendency of a PDZT head to erase adjacent tracks while retaining writeability and track width control. The present invention addresses such a need.